Role of neutral-beam fuelling profile in energy confinement and neutron emission on TFTR

The role of the neutral-beam fuelling profile in determining the stored energy and neutron emission in neutral-beam-heated discharges on TFTR is investigated. It is found that the neutral-beam fuelling profile is sensitive to both the magnitude and the shape of the electron density. The ion stored energy correlates well with the peaking of the neutral-beam fuelling profile, whereas the electron stored energy is insensitive to this parameter. The DD fusion neutron emission is also well correlated with the peaking of the neutral-beam fuelling profile. The derived empirical scalings of the ion stored energy and neutron yield include discharges from the L mode to the supershot regime